package com.shawn.test;

class Actor{
	public void act(){}
}
class HappyActor extends Actor {
	public void act(){System.out.println("HappyActor");}
}
class SadActor extends Actor {
	public void act(){System.out.println("SadActor");}
}
class Stage{
	private Actor actor = new HappyActor();
	public void change() {actor = new SadActor();}
	public void performPlay(){actor.act();}
}
public class Transmogrify {
	public static void main(String[] args) {
		Stage stage = new Stage();
		stage.performPlay();
		stage.change();
		stage.performPlay();
	}

}
